Refractive errors among patients attending the ophthalmology department of a medical college in North-East India

Epidemiology of eye diseases: outcomes from a free provincial eye clinic in Papua New Guinea

Aim

To ascertain the prevalence and pattern of eye problems in Madang Province, Papua New Guinea.

Materials and methods

A six-month retrospective study was performed at Madang Provincial Hospital Eye Clinic. Convenience sampling was used in this study and all patient records from January to June 2020 were included. Data was extracted using Microsoft Excel and the data included gender, age, occupation, district where the patient lived, presenting visual acuity, and diagnosis. It was then analyzed using International Business Machines Corporation's Statistical Package for the Social Sciences version 26. A p-value of ≤0.05 was considered statistically significant.

Results

A total of 1,715 patients received services at the eye clinic between January and June 2020, and 1,664 were included in this study. The mean age of the patients was 39.3 ± 20.3 years. There were slightly more males (50.4%) than females. The overall leading ocular morbidities were corneal ulcers and keratitis (20.7%), refractive errors (17.4%), and cataracts (16.8%). More than half of the patients (56.2%) were either visually impaired or blind. Nearly half of the patients (41.8%) traveled long distances to seek services at the eye clinic. There was a significant association between demographic characteristics, diagnosis, and level of visual impairment.

Conclusion

There is a high prevalence of potential causes of visual impairment and blindness in Madang Province and these conditions affect all age groups and genders. It is essential to increase accessibility to eye care services in the country.

Epidemiology and trends in the uptake of refractive error services in Harare, Zimbabwe: a hospital-based retrospective study

Aim

The study aimed to determine the epidemiology and evaluate the trends in the uptake of refractive error services in Harare.

Methods

A clinic-based retrospective study at the Greenwood Park Eye Centre and its three subsidiaries was conducted from January 1, 2015 to December 31, 2020.

Results

12,216 patients' records were retrieved, out of which 1074 (8.79%) had refractive error cases. The prevalence of visual impairment at presentation was 5.80% [95% CI: 5.39 - 6.23]. Among those with refractive error, the sample prevalence of visual impairment before correction was 41.30% [CI: 38.3 - 44.3, 95%], and 2.20% [95% CI: 1.4 - 3.3] after correction. There was inconsistency in the percentage utilization of refractive error services, with the highest being 42.60% in 2015. Refractive error types were related to age, employment position, and type of visual impairment prior to refractive error treatment.

Conclusion

There was a low percentage of refractive error services uptake in urban Zimbabwe.

The Magnitude of Refractive Error and Its Associated Factors Among Patients Visiting Ophthalmology Clinics in Southern Ethiopia, 2022

Introduction

Refractive error is a vision-impairing condition due to light rays not being able to focus on the retina, resulting in the visual outcome of a cloudy image. It is one of the main causes of central vision impairment globally and in Africa, including Ethiopia. This study was conducted to assess the magnitude of refractive error and its associated factors among patients attending ophthalmic clinics.

Methods

An institutional-based cross-sectional study design was utilized. A systematic random sampling technique was applied to select 356 participants. The data were gathered using an interview-structured questionnaire and check list. Then, the data were entered into Epi-data version 4.6 and transferred to SPSS version 25 for further clean up and analysis. Descriptive and analytical statistics were conducted. A binary logistic regression analysis was done, and variables with a p-value of less than 0.25 in univariate analysis were taken for bivariate analysis. Statistically significant was declared at a p-value of less than 0.05 with an adjusted odds ratio and 95% confidence interval.

Results

Among 356 participants, 96 (27.5%), with 95% CI (22.8, 32.1) had a refractive error, of which nearsighted is the most common type (15.8%). Regular use of electronic devices, near working distance (<33cm), less or lack of outdoor activities, history of diabetes mellitus and family history of refractive error were factors significantly associated with refractive error.

Conclusion and Recommendations

The magnitude of refractive error was 27.5%, which is relatively elevated than the previous studies. Clients need to get screened regularly so that refractive defects can be detected and corrected early. Eye care professionals shall make a big concern for patients with a history of diabetes and other medical illnesses since they are related to ocular refractive defects.

Prediction of manifest refraction using machine learning ensemble models on wavefront aberrometry data

PURPOSE

To assess the performance of machine learning (ML) ensemble models for predicting patient subjective refraction (SR) using demographic factors, wavefront aberrometry data, and measurement quality related metrics taken with a low-cost portable autorefractor.

METHODS

Four ensemble models were evaluated for predicting individual power vectors (M, J0, and J45) corresponding to the eyeglass prescription of each patient. Those models were random forest regressor (RF), gradient boosting regressor (GB), extreme gradient boosting regressor (XGB), and a custom assembly model (ASB) that averages the first three models. Algorithms were trained on a dataset of 1244 samples and the predictive power was evaluated with 518 unseen samples. Variables used for the prediction were age, gender, Zernike coefficients up to 5th order, and pupil related metrics provided by the autorefractor. Agreement with SR was measured using Bland-Altman analysis, overall prediction error, and percentage of agreement between the ML predictions and subjective refractions for different thresholds (0.25 D, 0.5 D).

RESULTS

All models considerably outperformed the predictions from the autorefractor, while ASB obtained the best results. The accuracy of the predictions for each individual power vector component was substantially improved resulting in a ± 0.63 D, ±0.14D, and ±0.08 D reduction in the 95% limits of agreement of the error distribution for M, J0, and J45, respectively. The wavefront-aberrometry related variables had the biggest impact on the prediction, while demographic and measurement quality-related features showed a heterogeneous but consistent predictive value.

CONCLUSIONS

These results suggest that ML is effective for improving precision in predicting patient's SR from objective measurements taken with a low-cost portable device.

Myopia in India

India is a culturally and geographically diverse nation. Its vast demographic nature does not allow a single definition for any of the given medical conditions in its territory. One important clinical condition which has created an uproar in the rest of the world is myopia. Its cause, prevalence, etiopathogenesis and other factors are being explored constantly; however, data with respect to Indian subcontinent are genuinely missing. Hence, in this review, we enumerate the country’s myopia journey from last 4 decades. The epidemiology, genetics, ocular/systemic association, quality of life, imaging, and management in myopia with necessary future directives are discussed to augment the overall management in future.

Gender and age distribution of refractive errors in an optometric clinical population

AIM

To determine the patterns of distribution of refractive errors in a clinical sample of patients examined in an optometry practice.

METHOD

In this retrospective study, the clinic records of 6687 patients aged 6 to 85 years comprising 2168 (32.2%) males and 4519 (67.5%) females were reviewed. Refractive error were analysed according to gender, age, as well as types and categories including axis of astigmatism using the vector power analysis method where the traditional sphero-cylinder was transformed into J0 (primary) and J45 (oblique) astigmatic components.

RESULTS

Only the analysis for right eye was reported as right and left spherical equivalent were similar. The mean with standard deviations for refractive errors were: Myopia: -1.95 ± 2.6, hyperopia: 1.04  ± 0.9, astigmatism: -1.22 ± 0.71 and anisometropia: -0.01 ± 2.5 DS. The distributions with significant changes included males that were significantly more myopic and astigmatic, while females were more hyperopic across the age groups. Furthermore, myopia decreased, while hyperopia, astigmatism and anisometropia increased with increasing age. Unique findings from this study include: myopia peaked earlier, second hyperopic shift commenced after age 82 years and the distribution of severity of astigmatism contrasts with previous understanding.

CONCLUSION

Although the patterns of distribution of refractive errors in patients aged 6 to 85 years corroborates previous findings, myopia and hyperopia peak, as well as severity of astigmatism were unique to the present study. Results from non-clinic populations will be useful to confirm trends reported in this study.